Conjunctivitis is inflammation of the inner and/or outer
surface of the eyelid. It is commonly caused by either an
allergic condition or a viral infection, and sometimes a
bacterial infection.

Environmental Causes

In domestic rabbits it is fairly common (over thirty
percent) for a rabbit to develop conjunctivitis without an
infection. This is thought to often be caused by allergy or
irritation from hay dust rather than infection, although
infection can set into a chronically irritated eye.

If hay dust is determined to be the cause, using hay racks
with solid sides so dust is not spread out when the rabbits
are eating, and filling the hay rack elsewhere to keep down
the dust may solve the problem.

Environmentally caused Conjunctivitis often results in the
rabbit's having watery eyes. The tear ducts of a rabbit are
small, and even narrower at certain points, so irritation
can create more tears than the tear ducts can handle,
resulting in constantly watering eyes. Treating the
conjunctivitis and applying topical antibiotics often cures
the watery eyes as well.

Tooth Causes

Another cause of a rabbit's having constantly watering eyes
or chronic conjunctivitis is swollen roots of the cheek
teeth pressing on the tear duct. Your veterinarian may need
to X-ray to see what teeth are causing the problem, and the
offending teeth may need to be removed.

Some veterinarians believe that the roots of the incisors
may be damaged in the first few months of a rabbit's life if
it doesn't get enough Calcium and Vitamin D, so it is
important to feed your young rabbits a diet in which the
vitamins and minerals aren't in separate pellets that the
rabbits can fail to eat.

Infection

Myxomatosis or upper respiratory infections may cause
Conjunctivitis. In fact, Conjunctivitis should never be
ignored because it is often the first or only symptom of
another dangerous infection. If you aren't sure of the cause
of your rabbit's runny or matted eye, see your veterinarian
as soon as you can, so he or she can check for infections
elsewhere as well as in the rabbit's eyes.

Genetic Causes

Entropion of the eyelids, in which the eyelids roll inward
so that the eyelashes cause constant irritation to the
eyeball, can cause irritation of the cornea or
conjunctivitis as well.

First Aid

If your rabbit has a runny or matted eye and you can't see
your vet immediately, some rabbit keepers recommend washing
out the rabbit's eyes with a warm water wash with a few
drops of chamomile added to it, which they say can help to
relieve the rabbit's discomfort and promote healing of the
condition.